HE image. of the patient, leading to the occlusion of the right ureter with subsequent hydronephrosis. hybridization of immunoglobulin light chains showed restricted expression of immunoglobulin chain compared with chain (Physique 2E and ?and2F).2F). On the other hand, no apparent evidence for urothelial carcinoma was observed (Physique 2A). From these histopathological findings, a diagnosis of MALT lymphoma of the urinary bladder was made. The lymphoma lesion was associated with linens or aggregates of epithelioid histiocytes (Physique 3A), which was confirmed by CD68 immunohistochemistry (Physique 3B). Kossa staining of the aggregated histiocytes showed Michaelis-Gutmann body (Physique 3C), confirming the association of malakoplakia with MALT lymphoma. Together with the results of systemic examination and imaging studies, a final diagnosis of main MALT lymphoma with malakoplakia of the urinary bladder of clinical stage III was established. Open in a separate window Physique 2 Histology of the urinary bladder tumor. Rabbit Polyclonal to TEAD1 A. Hematoxylin and eosin (HE) image of the urothelial erosion by infiltration of the tumor cells. The tumor cells proliferate in a vaguely nodular fashion. PD173074 Residual urothelial epithelium is usually observed in the right-upper corner of the physique. Initial magnification: 200. Bar: 200 m; B. HE image of the tumor nodule. The tumor cells are small and medium-sized. Germinal centers are not evident. PD173074 Initial magnification: 400. Bar: 100 m; C. CD20 immunohistochemistry. The tumor cells are stained brown and CD20-positive. Initial magnification: 400. Bar: 100 m; D. CD3 immunohistochemistry. Most of the tumor cells are stained unfavorable. Initial magnification: 400. Bar: 100 m; E, F. hybridization of immunoglobulins (Ig) light chain (E) and light chain (F). Most of the tumor cells are positive for Ig (E) but unfavorable for Ig (F), suggesting monoclonal proliferation of the B lymphoid cells. Initial magnification: 400. Bar: 100 m. Open in a separate window Physique 3 Histology of malakoplakia. A. HE image. Epithelioid histiocytes are aggregated in a sheet-like manner; B. CD68 immunohistochemistry. The aggregated cells are positively stained; C. Kossa staining. The histiocytes contain black calcified Michaelis-Gutmann body. Initial magnification: 400. Bar: 100 m. After the PD173074 subsequent four courses of treatment with rituximab, the thickness of the lymphoma lesion decreased from 15 mm to 5 mm by abdominal ultrasonography (data not shown). Conversation Main MALT lymphoma of the urinary bladder is usually primarily a localized disease [1]. Its transformation into diffuse large B-cell lymphoma was reported [4]. Although large cell components were not apparent in the urinary bladder in our case, PET/CT examination revealed a mediastinal lesion, which was presumed to be a distant involvement of the bladder lymphoma. Main MALT lymphoma of the urinary bladder shows female predominance [1]. It is frequently associated with chronic cystitis [1]. One plausible pathological basis may be an induction of MALT tissue in the urinary bladder by chronic cystitis, a close parallel of MALT lymphomagenesis by gastric contamination with em Helicobacter pylori /em . It is generally known that MALT lymphoma may be associated with autoimmune diseases. However, in our case, there were no apparent evidences suggesting the presence of autoimmune disorders except the 40 fold titer PD173074 of anti-nuclear antibody (normal range: less than 40 fold). In addition, IgG4-positive plasma cells were only scatteredly observed immunohistochemically, excluding the possibility of IgG4-related disease (data not shown). In our case, malakoplakia was associated with the MALT lymphoma in the urinary bladder. The majority of the bladder tumor was occupied by the lymphoma cells, and malakoplakia was observed in part of the tumor. Supposedly, the lymphoma and the malakoplakia may share cystitis as a common etiology, or malakoplakia may be a reactive lesion against the lymphoma. Numerous histiocytic lesions were reported to be associated with MALT lymphoma, such as crystal-storing histiocytosis [5-14], hemophagocytosis [15], and Langerhans cell histocytosis [16]. However, no definite case of concurrent MALT lymphoma and malakoplakia was reported. There was only one case statement on lymphoma and malakoplakia in the urinary bladder [17]. However, in that case, the malakoplakia preceded the lymphoma and the histological subtype PD173074 of the lymphoma was not shown [17]. In general, malakoplakia occurs in immunocompromised hosts. It is possible that this rarity of malakoplakia may be related to the level of immunosuppression required. Here we statement.

HE image